import time
scale = 10
print("执行开始".center(scale//2, "-"))
start = time.perf_counter()
for i in range(scale+1):
    a='*'*i
    b='.'*(scale-i)
    c=(i/scale)*100
    dur = time.perf_counter()-start
    print("\r{:^3.0f}%[{}->{}]{:.2f}s".format(c,a,b,dur), end="")
    time.sleep(3)
print("\n"+"执行结束".center(scale//2, '-'))